I'm trying to pound the casting off the pylon in order to replace two sidebars on my H14. So far, I've turned the boat upside down on sawhorses, soaked the joint in (on different evenings) Liquid Wrench, Coca Cola, lacquer thinner,and some other penetrant. I have managed to loosen one rear corner, but the other one is putting up quite a battle. I have even tried heating the casting with a propane torch, and then hard pounding. Not a millimeter of movement. Any ideas on how to free up this really old joint (hull 3450)?Thanks in advance

Every solvent and/or applied heat effort failed, and so I had to carefully saw the casting off. After I did, I could tell how far the various so-called penetrants had penetrated into the white (aluminum oxide?) powder between the pieces.And that is to say they penetrated hardly at all. And this was with the boat inverted and the castings acting like cups to hold the penetrants in place. Of all four castings, only one budged under my penetrant/ hammer onslaught, thank goodness.I think this boat is from 1969 (hull # 3450), and it has been in lots of salt water since then. Glad I only had to buy one new(used, actually) casting in order to replace the sidebars